As stated in U.S. Pat. No. 4,843,544, the problem of transferring data from peripheral storage media such as punched cards, punched tape, magnetic tape, magnetic drums, magnetic discs and optical discs, has always been a major consideration as the technology of automatic data processing systems has advanced.
With the completion of the ANSI X3.131-1986 standard for the Small Computer System Interface (SCSI), the small computer industry set the goals for the next generation of small system peripheral interfaces and the interaction of peripheral storage media with such interfaces. The SCSI standard paves the way for a high data transfer rate between the SCSI bus and a peripheral storage device, such as a Winchester Disc System.
The Small Computer System Interface (SCSI-1) protocol is fully described in the American National Standard ANSI X3.131-1986 publication available from the American National Standards Institute, Inc., 1430 Broadway, New York, N.Y. 10018; and in the American National Standard Small Computer System Interface-2 (SCSI-2) 1991 publication, available from Global Engineering Documents, 2805 McGain, Irvine, Calif., 92714.
Generally, up to eight devices including small computers and peripherals, may be coupled to the SCSI bus. The SCSI bus includes data and control lines with bus protocol facilitating information transfer between the devices and the bus.
Soon after the completion of the ANSI X3.131 standard for small computer system interface (SCSI) various designs for SCSI disc controllers and drives began to be implemented. testers for such disc drives are presently on the market. Two companies, namely, ADAPTEC and FLEXSTAR are presently marketing programmable testers for testing SCSI interface disc drives. These testers are relatively simple and straightforward to program, but they are difficult to operate and interpret, especially for novice operators and those unfamiliar with programming.
The tester (or qualifer) of the present invention is constructed to make the abstract nature of SCSI small computer systems interface definition easier to understand and work with. When compared with available conventional SCSI PC Tools and development systems that tend to make SCSI definitions more complex and more difficult to understand, the qualifier of the present invention is designed to make the SCSI definition simpler. The qualifier of the invention uses a simple ami built-in concept which allows an operator quickly to become familiar with the SCSI Interface Protocol and command structure. and enables the operator to use the qualifier with built-in canned diagnostics to execute complex performance tests on a target with just a few key strokes.
The present invention provides a qualifier for SCSI magnetic disc drives, magnetic tape drives, optical drives and the like, which, in the embodiment to be described, is a portable stand-alone unit for testing and evaluating SCSI direct access and sequential access devices, in accordance with ANI SCSI-1 and ANSI SCSI-2 definitions. The qualifier of the present invention is completely menu driven, both for a novice and interactive (operation) users. All commands are executed with a single keystroke.
All of the definitions and vocabulary of the ANSI SCSI specifications contained in the documents referred to above are incorporated into the software of the qualifer of the invention. The drive being tested sends message and error codes to the qualifer, which has the ANSI definitions and vocabulary built into its software, so that the qualifer responds to the codes as is the case with the prior art machines, but also the corresponding ANSI definitions in plain language.
The qualifier of the invention includes a cathode ray tube (CRT) which displays a multiplicity of individual screens under the keyboard control of the operator, and which directly displays the ANSI defined names, labels and error messages in plain language for immediate comprehension by the operator.
Each screen is divided into two areas: (A) "Work Space" where all menus, data, error messages are displayed and (B) "Status Window" which displays the current status of the SCSI bus and of the qualifier. A built-in easy to use editor allows convenient access to command DESCRIPTOR BLOCKS, MODE SELECT parameters, FORMAT and DEFECT LISTS and HEADERS, and SEND DIAGNOSTIC sub-command headers. A built-in bus analyzer timing capability with high resolution permits the operator to measure all key timing events.
All menus, data, error messages, and the like, are formatted onto separate screens which may be readily selected by the operator and individually displayed by the CRT. Unlike the prior art testers, the flood of binary information flowing back and forth on the SCSI bus between the qualifier and the disc drive is interpreted by an internal data processor and produced on each screen in a plain language format which makes the abstract nature of SCSI definition easier to understand and work with, as compared with the prior art testers.
The qualifier of the invention is constructed to use a simple built-in feature which allows the operator quickly to become familiar with SCSI protocol and command structure, and enables the operator to execute complex performance tests on the equipment under test with relatively few keystrokes.
Even the novice operator can operate the qualifier of the invention and be furnished with all of the required data directly, without involving the need for reference to tables, or any particular skill on the part of the operator, in interpreting the data.
Convenient operations makes the qualifier of the invention easily adaptable for simple performance checks of a disc drive, or under equipment under test, by a low level technician; or to more sophisticated tests of the disc drive by a test engineer familiar with the SCSI definitions. In either case, no programming skills are required to operate the qualifier of the invention.
The principal objective of the present invention is to provide a SCSI qualifier constructed to reduce the confusion and effort previously required by the operator to evaluate and test SCSI devices. Wherever applicable, text and error messages on each screen displayed by the CRT 14 are in plain language identical to the ANSI SCSI-2 definitions contained in the standard documents referred to above.